feat(tools): centralize tool emoji metadata in registry + skin integration

- Add 'emoji' field to ToolEntry and 'get_emoji()' to ToolRegistry
- Add emoji= to all 50+ registry.register() calls across tool files
- Add get_tool_emoji() helper in agent/display.py with 3-tier resolution:
  skin override → registry default → hardcoded fallback
- Replace hardcoded emoji maps in run_agent.py, delegate_tool.py, and
  gateway/run.py with centralized get_tool_emoji() calls
- Add 'tool_emojis' field to SkinConfig so skins can override per-tool
  emojis (e.g. ares skin could use swords instead of wrenches)
- Add 11 tests (5 registry emoji, 6 display/skin integration)
- Update AGENTS.md skin docs table

Based on the approach from PR #1061 by ForgingAlex (emoji centralization
in registry). This salvage fixes several issues from the original:
- Does NOT split the cronjob tool (which would crash on missing schemas)
- Does NOT change image_generate toolset/requires_env/is_async
- Does NOT delete existing tests
- Completes the centralization (gateway/run.py was missed)
- Hooks into the skin system for full customizability

tests/agent/test_display_emoji.py

@@ -0,0 +1,123 @@
+"""Tests for get_tool_emoji in agent/display.py — skin + registry integration."""
+
+from unittest.mock import patch as mock_patch, MagicMock
+
+from agent.display import get_tool_emoji
+
+
+class TestGetToolEmoji:
+    """Verify the skin → registry → fallback resolution chain."""
+
+    def test_returns_registry_emoji_when_no_skin(self):
+        """Registry-registered emoji is used when no skin is active."""
+        mock_registry = MagicMock()
+        mock_registry.get_emoji.return_value = "🎨"
+        with mock_patch("agent.display._get_skin", return_value=None), \
+             mock_patch("agent.display.registry", mock_registry, create=True):
+            # Need to patch the import inside get_tool_emoji
+            pass
+        # Direct test: patch the lazy import path
+        with mock_patch("agent.display._get_skin", return_value=None):
+            # get_tool_emoji will try to import registry — mock that
+            mock_reg = MagicMock()
+            mock_reg.get_emoji.return_value = "📖"
+            with mock_patch.dict("sys.modules", {}):
+                import sys
+                # Patch tools.registry module
+                mock_module = MagicMock()
+                mock_module.registry = mock_reg
+                with mock_patch.dict(sys.modules, {"tools.registry": mock_module}):
+                    result = get_tool_emoji("read_file")
+                    assert result == "📖"
+
+    def test_skin_override_takes_precedence(self):
+        """Skin tool_emojis override registry defaults."""
+        skin = MagicMock()
+        skin.tool_emojis = {"terminal": "⚔"}
+        with mock_patch("agent.display._get_skin", return_value=skin):
+            result = get_tool_emoji("terminal")
+            assert result == "⚔"
+
+    def test_skin_empty_dict_falls_through(self):
+        """Empty skin tool_emojis falls through to registry."""
+        skin = MagicMock()
+        skin.tool_emojis = {}
+        mock_reg = MagicMock()
+        mock_reg.get_emoji.return_value = "💻"
+        import sys
+        mock_module = MagicMock()
+        mock_module.registry = mock_reg
+        with mock_patch("agent.display._get_skin", return_value=skin), \
+             mock_patch.dict(sys.modules, {"tools.registry": mock_module}):
+            result = get_tool_emoji("terminal")
+            assert result == "💻"
+
+    def test_fallback_default(self):
+        """When neither skin nor registry has an emoji, use the default."""
+        skin = MagicMock()
+        skin.tool_emojis = {}
+        mock_reg = MagicMock()
+        mock_reg.get_emoji.return_value = ""
+        import sys
+        mock_module = MagicMock()
+        mock_module.registry = mock_reg
+        with mock_patch("agent.display._get_skin", return_value=skin), \
+             mock_patch.dict(sys.modules, {"tools.registry": mock_module}):
+            result = get_tool_emoji("unknown_tool")
+            assert result == "⚡"
+
+    def test_custom_default(self):
+        """Custom default is returned when nothing matches."""
+        with mock_patch("agent.display._get_skin", return_value=None):
+            mock_reg = MagicMock()
+            mock_reg.get_emoji.return_value = ""
+            import sys
+            mock_module = MagicMock()
+            mock_module.registry = mock_reg
+            with mock_patch.dict(sys.modules, {"tools.registry": mock_module}):
+                result = get_tool_emoji("x", default="⚙️")
+                assert result == "⚙️"
+
+    def test_skin_override_only_for_matching_tool(self):
+        """Skin override for one tool doesn't affect others."""
+        skin = MagicMock()
+        skin.tool_emojis = {"terminal": "⚔"}
+        mock_reg = MagicMock()
+        mock_reg.get_emoji.return_value = "🔍"
+        import sys
+        mock_module = MagicMock()
+        mock_module.registry = mock_reg
+        with mock_patch("agent.display._get_skin", return_value=skin), \
+             mock_patch.dict(sys.modules, {"tools.registry": mock_module}):
+            assert get_tool_emoji("terminal") == "⚔"  # skin override
+            assert get_tool_emoji("web_search") == "🔍"  # registry fallback
+
+
+class TestSkinConfigToolEmojis:
+    """Verify SkinConfig handles tool_emojis field correctly."""
+
+    def test_skin_config_has_tool_emojis_field(self):
+        from hermes_cli.skin_engine import SkinConfig
+        skin = SkinConfig(name="test")
+        assert skin.tool_emojis == {}
+
+    def test_skin_config_accepts_tool_emojis(self):
+        from hermes_cli.skin_engine import SkinConfig
+        emojis = {"terminal": "⚔", "web_search": "🔮"}
+        skin = SkinConfig(name="test", tool_emojis=emojis)
+        assert skin.tool_emojis == emojis
+
+    def test_build_skin_config_includes_tool_emojis(self):
+        from hermes_cli.skin_engine import _build_skin_config
+        data = {
+            "name": "custom",
+            "tool_emojis": {"terminal": "🗡️", "patch": "⚒️"},
+        }
+        skin = _build_skin_config(data)
+        assert skin.tool_emojis == {"terminal": "🗡️", "patch": "⚒️"}
+
+    def test_build_skin_config_empty_tool_emojis_default(self):
+        from hermes_cli.skin_engine import _build_skin_config
+        data = {"name": "minimal"}
+        skin = _build_skin_config(data)
+        assert skin.tool_emojis == {}